Lpc2000

At 01:21 AM 10/11/04 +0000, you wrote:
>The best way around all these issues, IMHO, is to use an assember
>wrapper that calls C functions. The wrapper can then be tuned to meet
>all your needs (eg. supporting nested interrupts, thumb safety etc)
>in a far more predictable and controllable way than trying to do
>stuff in C.

As long as we are getting into religious discussions Amen! :)  I've seen C 
interrupt routines either have broken (non-functioning) implementations 
and/or so burdened with overhead as to be practically useless.

The wrapper approach is the one I take (and did with the newlib lpc 
stuff).  I also distrust inline assembly, I've seen it break too many 
compilers and I've yet to see an implementation that completely defined 
what was safe.  The documentation usually has a few words to the effect 
that if you "interfere with the registers the compiler is using for 
something else the results are undefined".  If I want or need assembly I 
write assembly, not assembly masquerading as C.

On the other hand I have heard that the newer versions of GCC do handle 
interrupts better.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III